The inventive concepts relate to film bulk acoustic resonator (FBAR) oscillators and gas sensing systems using the same.
An oscillator may include various circuits used for oscillation, together with a resonator. For example, the oscillator may generate an oscillating signal based on various types of resonator. Various types of resonators, such as a crystal type, a ceramic type, and a surface acoustic wave (SAW) type, may be included in the oscillator. As an example of the resonator, an FBAR may have a structure in which a lower electrode, a piezoelectric layer, and an upper electrode are sequentially stacked on each other, and uses a principle in which acoustic waves are generated by a piezoelectric effect when electric energy is applied to the lower and upper electrodes, and thus resonance may be generated.
The FBAR may be connected to a circuit (for example, an amplifier) such that the FBAR may actually generate an oscillating signal through a conductive line. In some cases, a parasitic element (for example, a parasitic inductance) may exist in an electric path through the conductive line. Accordingly, a spurious resonance may be generated, through the conductive line, in a frequency domain other than a resonance frequency, and thus performance of the oscillator may be deteriorated and in addition, performance of a system using the oscillator may be deteriorated.